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| United States Patent |
6,019,399
|
|
Sweeney
|
February 1, 2000
|
Split-ring fluid coupling for corrugated tubing and method of assembly
Abstract
A fluid coupling for connecting a corrugated tube to a fitting. The
coupling includes an annular compression member having an opening
therethrough which extends from a forward end portion receivable coaxially
over the tube to a rearward end portion threadably engagable with the
fitting to urge the tube into a fluid-tight engagement therewith. The
forward end portion of the opening has a rearward first end, a forward
second end defining the inner diametric extent of the opening, and an
inner radial surface extending therebetween from a rearward gland portion
to a forward camming portion. An annular locking member is journalled
within the gland to be received therewith over the tube. The locking
member is expandable within the gland by the crest portions of the tube as
the locking and compression members are received thereover, and is
compressible within a root portion of the tube responsive to the bearing
of the compression member camming surface thereon as the compression
member is threadably engaged with the fitting. When compressed, the
locking member delimits the forward advancement of the tube out of the
opening of the compression member.
| Inventors:
|
Sweeney; Michael A. (Kent, OH)
|
| Assignee:
|
Parker-Hannifin Corporation (Cleveland, OH)
|
| Appl. No.:
|
990206 |
| Filed:
|
December 13, 1997 |
| Current U.S. Class: |
285/248; 285/321; 285/334.5; 285/903 |
| Intern'l Class: |
F16L 037/18 |
| Field of Search: |
285/903,334.5,321,354,318,382.7,248,249
|
References Cited
U.S. Patent Documents
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| 2363586 | Nov., 1944 | Guarnaschelli.
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| 2496149 | Jan., 1950 | Cahenzli, Jr.
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| 2497273 | Feb., 1950 | Richardson.
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| 2503826 | Apr., 1950 | Lamont | 285/384.
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| 2549741 | Apr., 1951 | Young.
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| 2848254 | Aug., 1958 | Millar.
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| 2858147 | Oct., 1958 | Guarnaschelli.
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| 2946607 | Jul., 1960 | Bauer.
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| 2991093 | Jul., 1961 | Guarnaschelli.
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| 3008736 | Nov., 1961 | Samiran.
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| 3112937 | Dec., 1963 | Williams.
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| 3294426 | Dec., 1966 | Lyon.
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| 3381980 | May., 1968 | Smith.
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| 3454290 | Jul., 1969 | Tairraz.
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| 3888522 | Jun., 1975 | Moreiras | 285/382.
|
| 4046451 | Sep., 1977 | Juds et al.
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| 4136897 | Jan., 1979 | Haluch.
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| 4423891 | Jan., 1984 | Menges.
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| 4630850 | Dec., 1986 | Saka.
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| 4669761 | Jun., 1987 | Huling.
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| 4674775 | Jun., 1987 | Tajima et al.
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| 4867489 | Sep., 1989 | Patel.
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| 4872710 | Oct., 1989 | Konecny et al. | 285/318.
|
| 4904002 | Feb., 1990 | Sasa et al.
| |
| 4907830 | Mar., 1990 | Sasa et al.
| |
| 4909547 | Mar., 1990 | Guy.
| |
| 5080405 | Jan., 1992 | Sasa et al.
| |
| 5131145 | Jul., 1992 | Badoureauz.
| |
| 5226682 | Jul., 1993 | Marrison et al.
| |
| 5261707 | Nov., 1993 | Kotake et al.
| |
| 5292156 | Mar., 1994 | Sasa et al.
| |
| 5356181 | Oct., 1994 | Shirogane et al.
| |
| 5413147 | May., 1995 | Moreiras et al.
| |
| 5423578 | Jun., 1995 | Kanomata et al.
| |
| 5441312 | Aug., 1995 | Fujiyoshi et al.
| |
| 5489127 | Feb., 1996 | Anglin et al.
| |
| 5543582 | Aug., 1996 | Stark et al.
| |
| 5580105 | Dec., 1996 | Miller, Jr. et al.
| |
| 5799989 | Sep., 1998 | Albino.
| |
| Foreign Patent Documents |
| 0 331 116 | Sep., 1989 | EP.
| |
| 0 545 410 | Jun., 1993 | EP.
| |
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| |
| 1371609 | Oct., 1974 | GB.
| |
| WO998/06970 | Feb., 1998 | WO.
| |
Other References
Design and Installation Guide dated Apr. 1996 of Gastite.
Literature on TracPipe, entitled "TracPipe Runs Circles Aroud Black Iron
Pipe" of Mestek, Inc.
|
Primary Examiner: Nicholson; Eric K
Attorney, Agent or Firm: Molnar, Jr.; John A.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional No. 60/035,901,
filed Jan. 23, 1997.
Claims
What is claimed is:
1. A coupling for connecting a distal end of a corrugated tube in fluid
communication with a fitting of a variety having a forward end with an
externally threaded surface, the tube being formed of alternating crest
portions defining the outer periphery of the tube and root portions, said
coupling comprising:
a generally annular compression member having an opening therethrough
extending axially along a central longitudinal axis from a forward end
portion of an inner diametric extent receivable coaxially over the distal
end of the tube to an internally-threaded rearward end portion threadably
engagable with the externally-threaded forward end of the fitting, said
opening forward end portion extending axially along said central
longitudinal axis from a rearward first end to a forward,
radially-inwardly extending second end which defines the inner diametric
extent of said opening, and having an inner radial surface extending
intermediate said first and seconds ends from a rearward circumferential
gland having a forward and a rearward end wall to a forward
circumferential camming surface; and
an annular one-piece split ring member journalled coaxially within said
gland of said compression member to be received therewith over the distal
end of the tube for disposition into a root portion thereof, said split
ring member being retained axially in said gland intermediate the forward
and rearward end walls thereof and being resiliently expandable radially
outwardly within said gland in response to the bearing of the crest
portions of the tube thereon to an expanded diameter accommodating the
passage of the outer periphery of the tube therethrough for said split
ring member and compression member to be received over the distal end of
the tube, and being resiliently compressible radially inwardly within said
root portion of the tube in response to the bearing of the camming surface
of said compression member thereon as said compression member is
threadably engaged with the fitting to a compressed diameter delimiting
the forward advancement of the tube distal end out of said opening of said
compression member.
2. The coupling of claim 1 wherein said split ring member has a generally
circular, oblique, or polygonal cross-sectional profile.
3. The coupling of claim 1 wherein said first end of said compression
member opening forward end portion extends radially inwardly to a
circumferential shoulder portion which defines said rearward end wall of
said gland.
4. The coupling of claim 1 wherein said gland of said compression member
opening forward end is configured as a generally
circumferentially-continuous, annular groove.
5. A fluid coupling assembly for connecting a distal end of a corrugated
tube in fluid communication with a fitting of a variety having an
externally-threaded forward end which terminates in a generally forwardly
tapered surface, the tube being formed of alternating crest portions
defining the outer periphery of the tube and root portions, and the distal
end thereof terminating at a first crest portion, said coupling
comprising:
a generally annular compression member having an opening therethrough
extending axially along a central longitudinal axis from a forward end
portion of an inner diametric extent received coaxially over the distal
end of the tube to an internally-threaded rearward end portion threadably
engagable with the externally-threaded forward end of the fitting, said
opening forward end portion extending axially along said central
longitudinal axis from a rearward first end to a forward,
radially-inwardly extending second end which defines the inner diametric
extent of said opening, and having an inner radial surface extending
intermediate said first and seconds ends from a rearward circumferential
gland having a forward and a rearward end wall to a forward
circumferential camming surface; and
an annular one-piece split ring member journalled coaxially within said
gland of said compression member and received therewith over the distal
end of the tube into a root portion thereof, said split ring member being
retained axially in said gland intermediate the forward and rearward end
walls thereof and being resiliently expanded radially outwardly within
said gland responsive to the bearing of the crest portions of the tube
thereon to an expanded diameter accommodating the passage of the outer
periphery of the tube therethrough for said split ring member to be
received with said compression member received over the distal end of the
tube, and being resiliently compressible radially inwardly within said
root portion of the tube responsive to the bearing of the camming surface
of said compression member thereon as said compression member is
threadably engaged with the fitting to a compressed diameter delimiting
the forward advancement of the tube distal end out of said opening of said
compression member.
6. The assembly of claim 5 wherein said ring member has a generally
circular, oblique, or polygonal cross-sectional profile.
7. The assembly of claim 5 wherein said first end of said compression
member opening forward end portion extends radially inwardly to a
circumferential shoulder portion which defines said rearward end wall of
said gland.
8. The assembly of claim 5 wherein said gland of said compression member
opening forward end is configured as a generally
circumferentially-continuous, annular groove.
9. A method of coupling a distal end of a corrugated tube in fluid
communication with a fitting of a variety having an externally-threaded
forward end which terminates in a generally forwardly tapered surface, the
tube being formed of alternating crest portions defining the outer
periphery of the tube and root portions, and the distal end thereof
terminating at a first crest portion, said method comprising the steps of:
(a) providing a generally annular compression member having an opening
therethrough extending axially along a central longitudinal axis from a
forward end portion of having a first inner diametric extent receivable
coaxially over the distal end of the tube to an internally-threaded
rearward end portion threadably engagable with the externally-threaded
forward end of the fitting, said opening forward end portion extending
axially along said central longitudinal axis from a rearward first end to
a forward, radially-inwardly extending second end which defines the first
inner diametric extent of said opening, and having an inner radial surface
extending intermediate said first and seconds ends from a rearward
circumferential gland having a forward and a rearward end wall to a
forward circumferential camming surface;
(b) journalling an annular one-piece split ring member coaxially within
said gland of said compression member, said split ring member being
retained axially in said gland intermediate the forward and rearward end
walls thereof and being resiliently expandable radially outwardly within
said gland to an expanded diameter, and being resiliently compressible
radially inwardly to a compressed diameter;
(c) advancing the distal end of the tube rearwardly through the opening of
said compression member to dispose said split ring member in a root
portion of the tube, said split ring member being expanded radially
outwardly within said gland of said compression member responsive to the
bearing of the crest portions of the tube thereon to said expanded
diameter accommodating the passage of the outer periphery of the tube
therethrough; and
(d) threadably engaging said rearward end portion of said compression
member with the forward end of the fitting, said split ring member being
resiliently compressed radially inwardly within said root portion of the
tube responsive to the bearing of the camming surface of said compression
member thereon to said compressed diameter delimiting the forward
advancement of the tube distal end out of said compression member opening.
10. The method of claim 9 wherein said ring member has a generally
circular, oblique, or polygonal cross-sectional profile.
11. The method of claim 9 wherein said compression member is provided in
step (a) with said first end of said opening forward end portion extending
radially inwardly to a circumferential shoulder portion which defines said
rearward end wall of said gland.
12. The method of claim 9 wherein said compression member is provided in
step (a) with said gland of said opening forward end being configured as a
generally circumferentially-continuous, annular groove.
13. The method of claim 9 further comprising the additional step between
steps (c) and (d) of flaring the distal end of the tube to collapse at
least the first crest portion thereof to present a rearwardly tapered
surface configured for an abutting, fluid-tight engagement with the
forwardly tapered surface of the fitting.
14. The method of claim 9 further comprising the additional step prior to
step (b) of providing an assembly tool comprising:
a cylindrical outer guide member configured to receive said split ring
member therein, and being insertable within the opening of said
compression member through the rearward end portion thereof; and
a cylindrical inner plunger member received within said outer member for
sliding movement from a rearward first position to a forward second
position, and
wherein said split ring member is journalled within said compression member
in step (b) by receiving said split ring member within the guide member of
the tool, inserting the guide member within the opening of said
compression member, and moving the plunger member from its first to its
second position urging said split ring member from the guide member and
into said gland of said compression member.
15. The method of claim 9 wherein said split ring member of step (b) has a
normal inner diameter smaller than the outer periphery of the tube
retaining said compression member on the tube.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a coupling for connecting
corrugated tubing with a fitting, and more particularly to a coupling
which includes an internally-received, split ring member which facilitates
the assembly of the coupling.
Corrugated tubing, often fabricated of stainless steel, copper, or the like
and jacketed with a plastic material, is commonly employed in residential
or commercial building constructions as a transitional fluid conduit
extending between an appliance or other machine and a rigid auxiliary
line, pipe, or other connection of a fuel source which typically is
natural gas, propane, or the like. The flexibility of such tubing
facilitates the alignment of couplings and other connections, and also
accommodates limited movement of the appliance or machine with respect to
the rigid connection of the fuel source.
More recently, tubing of such type has been proposed as a substitute for
traditional hard, i.e., inflexible, steel or iron "black" pipe in gas line
applications residential and commercial construction. Again, the
flexibility of the tubing facilitates its installation through walls,
ceilings, and floors and, especially, the alignment of the tubing
connections. Such tubing, moreover, is lightweight, easy to carry,
requires no threading or heavy equipment therefor, allows the use of fewer
fitting connections, and exhibits less leak potential than conventional,
hard piping. Corrugated tubing of the type herein involved additionally is
used in other fluid transport applications such as in air conditioning,
hydraulics, and general plumbing, and also as conduit for electrical
applications.
It is common practice to terminate either or both of the distal ends of a
length of corrugated tubing with a coupling for providing a leak-free
connection or other transition, and/or for effecting a mechanical locking
of the tubing ends limiting their movement under pressure or force. For
example, U.S. Pat. Nos. 5,441,312; 4,630,850; 4,674,775; and 2,323,912
disclose couplings of such type which generally comprise a sleeve and a
cap nut. The sleeve and nut are coaxially received over a distal end of
the tube for connection to a fitting associated with the auxiliary line or
the appliance.
Commonly-assigned, co-pending provisional application U.S. Ser. No.
60/017,227, filed May 9, 1996, discloses a coupling for connecting a
distal end of a corrugated tube with a fitting having a forward coupling
end with a tapered surface. The coupling includes a collet having a
circumferential wall portion which extends axially from a forward first
end to a rearward second end. The second end is configured as having an
outer portion and an inner portion of a second diameter smaller than the
outer periphery of the tube. The inner portion is configured to be
receivable within the root portions of the tube for retaining the collet
thereon, and presents a generally rearwardly-facing compression surface.
The wall portion is longitudinally dissected through the second end
thereof into at least a pair of arcuate, cantilevered segments. Each
segment is resiliently yieldable for radial outward movement allowing the
tube crest portions to be received through the second end of the wall
portion as the collet is advanced forwardly over the distal end of the
tube into retention within one of the root portions. A fastening member is
journalled over the collet second end and is engagable with the coupling
end of the fitting to draw the collet and the distal end of the tube
toward the fitting. The fastening member has an inner radial surface
extending to a rearwardly-facing shoulder portion configured to abuttingly
engage the outer portion of the collet second end for urging the collet
rearwardly toward the fitting compressing at least the first crest portion
of the fitting distal end between the tapered surface of the fitting and
the compression surface of the collet.
Young, U.S. Pat. No. 2,549,741, discloses a pipe joint which includes a
coupling nut adapted for a threaded connection with a spigot member. The
coupling nut has an internal groove for receiving a split ring, and the
spigot member has a conical surface for receiving the flared surface of a
pipe. Upon the tightening of the nut on the spigot member, the split ring
is made to compresses the flared pipe surface against the spigot.
Sasa et al., U.S. Pat. No. 4,904,002, discloses a fluid coupling for a
corrugated pipe which includes a body having a fluid passage, and an outer
sleeve having a collar which retains a pair of C-rings. The outer sleeve
is adapted to reduce the diameter of the C-rings such that the rings are
forced into the root portions of the corrugated pipe wherein the rings are
held axially in position.
Sasa et al., U.S. Pat. No. 5,080,405, discloses another coupling for
corrugated pipe which includes an inner cylindrical section having an
annular groove for receiving a split ring. The groove extends from a
forward flange portion to a rearward tapered surface which is formed on
the groove. Upon the insertion of an end of the pipe into the cylindrical
section, the ring is urged into a corrugation of the corrugated pipe by
the tapered surface of the groove.
Sasa et al., U.S. Pat. No. 5,292,156, discloses another fluid coupling for
a corrugated pipe. The coupling includes a locking cylinder having a
groove which accommodates the radial expansion of a ring received therein
when the end of a corrugated pipe is inserted into the cylinder.
Hughes, U.K. Patent No. 1,371,609, discloses another joint for a corrugated
pipe which includes a fitting to which a nut is threadably connected. The
nut is formed as having a groove portion for retaining a split compression
ring. Upon the insertion of an end of the pipe into the nut, the split
ring is urged into a into a corrugation of the pipe. The nut then may be
tightened on the fitting for drawing the pipe inward into a fluid-tight
connection.
Marrison et al., U.S. Pat. No. 5,226,682 discloses a coupling including a
first and second member and an annular locking ring interposable
therebetween. For receiving the locking ring, the first member is provided
as having an exterior surface with a groove, and the second member is
provided as having an inner surface with a cavity. The first and second
members are secured together when the locking ring is engaged in the
groove ands the cavity.
Another coupling for corrugated tubing is marketed commercially by Titeflex
Corp., Springfield, Mass. As is described in the Titeflex publication
"Gastite.TM. Design and Installation Guide," April 1996, such coupling
employs a two-piece metal split ring for positioning a swivel nut. The nut
is slidably mounted over the end of the tubing, and the split rings are
positioned in the valley, i.e., root or trough, of the first convolution
of the corrugations. The nut then is advanced toward the end of the tubing
to capture the split rings. A socket flaring tool next is threaded into
the nut and tightened. The tightening of the flaring tool compresses the
first convolution of the tubing to form a flared seat. The nut lastly is
threadably engaged with a corresponding end of the fitting.
However, the provision of two-piece split rings has been observed to
complicate the assembly of the coupling. For example, as being of a
relatively small size and separate from the nut, there is the potential
for the rings to be lost or simply forgotten during installation. One or
both of the rings might also fall out of the tubing prior to the
connection of the nut to the fitting. If either of the rings is
accidentally omitted, the tubing cannot be sealed to the fitting and a
hazardous leak may result.
As the use of corrugated tubing in gas line and other fluid transfer
applications continues to increase, it will be appreciated that further
improvements in the design of couplings therefor would be well-received by
both industry and consumers alike. A preferred design would be economical
to manufacture, but would also simplify the assembly of the coupling while
providing a connection which minimizes the potential for leaks and the
like.
SUMMARY OF THE INVENTION
The present invention is directed to a coupling for corrugated tubing, and
more particularly to a female coupling assembly for threadably connecting
the end of a length of corrugated tubing to an associated male fitting.
The assembly includes a nut or the like having an internal gland which
extends from a forward shoulder portion to a rearward camming surface. An
annular locking member, such as split wire ring is retained within the
gland intermediate the forward shoulder portion and rearward camming
surface thereof. Within the gland, the locking member is deflectable from
a normal to an expanded inner diameter by the rearward insertion of the
tubing end through the nut. After the insertion, the locking member is
deflected by the camming surface of the nut into one of the corrugations
of the tubing for the positive retention of the retaining the nut on the
tubing end. Advantageously, the one-piece locking member of the invention
may be pre-installed and retained within the nut during manufacture. In
this way, assembly of the coupling is simplified to better ensure that a
leak-free or other secure connection is obtained.
It therefore is a feature of a preferred embodiment of the present
invention to provide a coupling for connecting the distal end of a
corrugated tube in fluid communication with a fitting having a forward
coupling end with an externally-threaded surface. The coupling includes an
annular compression member having an opening therethrough which extends
from a forward end portion receivable coaxially over the tube to a
rearward end portion threadably engagable with the fitting to urge the
tube into a fluid-tight engagement therewith. The forward end portion of
the opening has a rearward first end, a forward second end defining the
inner diametric extent of the opening, and an inner radial surface
extending therebetween from a rearward gland portion to a forward camming
portion. An annular locking member is journalled within the gland to be
received therewith over the tube. The locking member is expandable within
the gland by the crest portions of the tube as the locking and compression
members are received thereover, and is compressible within a root portion
of the tube responsive to the bearing of the compression member camming
surface thereon as the compression member is threadably engaged with the
fitting. When compressed, the locking member delimits the forward
advancement of the tube out of the opening of the compression member.
It is a further feature of the preferred embodiment of the present
invention to provide a fluid coupling assembly for connecting the distal
end of a corrugated tube in fluid communication with a fitting having a
forward coupling end with an externally-threaded surface. The assembly
includes an annular compression member having an opening therethrough
which extends from a forward end portion received coaxially over the tube
to a rearward end portion threadably engagable with the fitting to urge
the tube into a fluid-tight engagement therewith. The forward end portion
of the opening has a rearward first end, a forward second end defining the
inner diametric extent of the opening, and an inner radial surface
extending therebetween from a rearward gland portion to a forward camming
portion. An annular locking member is journalled coaxially within the
gland and is received therewith over the tube. The locking member is
expandable within the gland by the crest portions of the tube as the
locking and compression members are received thereover, and is
compressible within a root portion of the tube responsive to the bearing
of the compression member camming surface thereon as the compression
member is threadably engaged with the fitting. When compressed, the
locking member delimits the forward advancement of the tube out of the
opening of the compression member.
It is yet a further feature of the preferred embodiment of the present
invention to provide a method of coupling a distal end of a corrugated
tube in fluid communication with a fitting of a variety having an
externally-threaded forward end. In accordance with the method, a
compression member is provided as having an opening therethrough extending
which extends from a forward end portion receivable coaxially over the
distal end of the tube a rearward end portion threadably engagable with
the fitting. The forward end portion of the opening has a rearward first
end, a second end defining the inner diametric extent of the opening, and
an inner radial surface extending therebetween from a rearward gland
portion to a forward camming portion. An annular locking member is
journalled within the gland of the compression member to be received
therewith over the distal end of the tube. The distal end of the tube then
is advanced rearwardly through the opening of the compression member to
dispose the locking member in a root portion of the tube retaining the
compression member thereon. As the tube is advanced through the opening,
the locking member is expanded within the gland to accommodate the crest
portions of the tube. Lastly, the rearward end portion of the compression
member is threadably engaged with the fitting urging the distal end of the
tube into a fluid-tight engagement therewith. As the compression member is
threaded onto the fitting, the locking member is thereby compressed within
the root portion of the tube responsive to the bearing of the camming
surface thereon. The compression of the locking member delimits the
forward advancement of the tube distal end out of the compression member
opening.
Advantages of the present invention include a coupling construction for
corrugated tubing which simplifies assembly with better assurance that a
leak-free connection is attained. Additional advantages include a coupling
construction which provides for the retention and positive positioning of
a one-piece locking member, and which effects a fluid-tight connection of
the tubing to an associated fitting. Still other advantages include a
coupling which is economical to manufacture and assemble, and which is
capable of withstanding prolonged exposure to natural gas and other
hydrocarbons at relatively high service pressures. These and other
advantages will be readily apparent to those skilled in the art based upon
the disclosure contained herein.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the invention,
reference should be had to the following detailed description taken in
connection with the accompanying drawings wherein:
FIG. 1 is an exploded, perspective view of a split ring coupling
constructed in accordance with the present invention for connecting the
distal end of a length of corrugated tubing in fluid communication with an
associated fitting;
FIG. 2 is a longitudinally-sectioned side view showing the coupling of FIG.
1 as assembled and received over the distal end of the tubing for the
connection thereof to the fitting;
FIG. 3A is a detailed top view showing the split ring of the coupling of
FIG. 2 in a compressed orientation;
FIG. 3B is a detailed top view showing the split ring of FIG. 3A in an
expanded orientation;
FIG. 4A is a partial cross-sectional views of the split ring of FIGS. 1 and
2 showing the generally circular cross-sectional profile thereof;
FIGS. 4B-D are partial cross-sectional views depicting representative
alternative cross-sectional profiles for the split ring of FIGS. 1 and 2;
FIG. 5 is a partial longitudinally-sectioned side view of the coupling of
FIG. 1 showing the mounting of the split ring thereof;
FIG. 6 is a partial longitudinally-sectioned side view of the coupling of
FIGS. 1 and 2 showing the expansion of the split ring thereof responsive
to the insertion of the tubing distal end;
FIG. 7 is a partial longitudinally-sectioned side view of the coupling of
FIG. 6 showing the disposition of the split ring thereof into a root
portion of one of the tubing corrugations;
FIG. 8 is a partial side view of the coupling of FIG. 7 showing the flaring
of the tubing distal end; and
FIG. 9 is a partial side view showing the connection of the coupling of
FIG. 2 to its associated fitting;
The drawings will be described further in connection with the following
Detailed
DETAILED DESCRIPTION OF THE INVENTION
Certain terminology may be employed in the description to follow for
convenience rather than for any limiting purpose. For example, the terms
"forward" and "rearward" designate directions in the drawings to which
reference is made, with the terms "radial" and "axial" referring,
respectively, to directions perpendicular and parallel to the longitudinal
central axis of the referenced element. Terminology of similar import
other than the words specifically mentioned above likewise is to be
considered as being used for purposes of convenience rather than in any
limiting sense.
For the purposes of the discourse to follow, the precepts of the invention
herein involved are described in connection with a corrugated tubing
coupling and assembly therefor particularly adapted for use in fuel gas
line applications in residential or commercial construction such as for
connecting an appliance or the like to a fuel gas source. It will be
appreciated, however, that aspects of the present invention may find
utility in other conduit systems, whether for fluids or for electrical or
other applications which utilize corrugated tubing. Use within those
systems therefore should be considered to be expressly within the scope of
the present invention.
Referring then to the figures wherein corresponding reference characters
are used to designate corresponding elements throughout the several views,
shown generally at 10 is an assembly according to the present invention
for connecting the distal end, 12, of a length of corrugated tubing,
represented generally at 14, in fluid communication with a fitting,
represented generally at 16. Fitting 16, which is formed of a generally
tubular body, 17, with an axial bore, 18, therethrough, is shown to be of
a variety having an externally-threaded forward coupling end, 20, which
terminates in a generally forwardly-tapered surface, 22. The rearward end,
24, of fitting 16 similarly may be externally-threaded for connection to
an auxiliary line of a fuel source, to an appliance or the like (not
shown), or to another conduit. Body 17 of fitting 16 additionally may be
formed as having a radial flange, 26, with hexagonal flats portion, one of
which is referenced at 28, configured for engagement with a wrench or
other tool during installation or connection.
Tubing 14, which may be constructed of stainless steel or another metallic
material, is conventionally formed of a sinusoidal series of uniform
corrugations or convolutions, a first one of which is referenced at 30. As
may be best seen through momentary reference to FIG. 7, wherein a partial
longitudinally-sectioned side view of tubing 14 is shown in schematic, the
convolutions define alternating crest portions which, as is shown at line
32, define the outer periphery of tubing 14, and root or trough portions
which extend radially inwardly from outer periphery 32. Distal end 12 of
tubing 14 is sectioned or otherwise formed to terminate at a first crest
portion, 34, having an associated first root portion, 36.
Returning to FIG. 1, assembly 10 includes, in accordance with the precepts
of the present invention, a coupling, referenced generally at 38, which,
in turn, includes a generally annular locking member, 40, and an
associated compression member, represented generally at 42. Preferably,
compression member 42 is configured as a cap nut or the like having
hexagonal flats portion, one of which is referenced at 44, for engagement
with a wrench or other tool during its threaded connection with fitting
16. Looking additionally to FIG. 2 wherein coupling 38 is shown as
assembled, compression member 42 may be seen to be formed as having an
axial opening, represented at 46, extending therethrough along a central
longitudinal axis, 48, from a forward end portion, 50, of an inner
diametric extent, do, which is received coaxially over the distal end 12
of tubing 14, to an internally-threaded reward end portion, 52, which is
threadably engagable with the externally-threaded forward end 20 of
fitting 16. As received over the tubing distal end, the forward end
portion 50 of opening 46 extends, in turn, axially along axis 48 from a
rearward first end, 54, to a radially-inwardly extending or flanged second
end, 56, which defines the inner diametric extent do of opening 46.
Forward end portion 50 additionally is formed as having an inner radial
surface, 58, extending intermediate first and second ends 54 and 56 from a
rearward circumferential gland or groove portion, referenced at 60, to a
forward circumferential camming surface, 64. Camming surface 64, which is
provided as a rearwardly-inclined, ramped or tapered surface, defines an
acute angle, referenced at .theta., of from about 5.degree.-45.degree.
with longitudinal axis 48 which is shown in phantom at 48'. Gland portion
60, which is configured to receive ring member 40 therein, is bounded by a
generally upstanding rearward end wall, 66, and a forward end wall defined
by camming surface 64. Optionally, and as is shown at 68, the forward end
wall of camming surface 64 may be configured to define a second acute
angle, .alpha., with axis 48'. As is also shown, rearward first end 54 of
opening forward end portion 50 preferably is provided to extend radially
inwardly to a circumferential shoulder portion, 70, defining, in turn, the
upstanding rearward end wall 66 of gland 60.
Locking member 40 is journalled coaxially within gland 60 of compression
member 42 to be received therewith over the distal end 12 of tubing 14.
Looking to FIG. 3, locking member 40 may be seen to be provided in a
preferred embodiment of the invention as a resilient split ring which
compressible radially inwardly, as is shown in FIG. 3A, to a compressed
diameter having inner and outer dimensions, d.sub.ci and d.sub.c,
respectively. Locking member 40 is likewise resiliently expandable
radially outwardly, as is shown in FIG. 3B, by a angular distance,
.omega., to an expanded diameter having expanded inner, d.sub.ei, and
outer, d.sub.eo, component dimensions. By "resilient," it is meant that
ring 40 exhibits a degree of hysteresis or elastic deformation, i.e.,
spring or "snap-back," to be alternately compressible or expandable from a
normal inner diameter which is intermediate expanded inner diameter
d.sub.ei and compressed inner diameter d.sub.ci.
Preferably, ring 40 is configured such that it assumes a generally circular
geometry about the tubing distal end when compressed. In this regard, ring
40 may be constructed from a length of an extruded wire material which is
cold worked or otherwise formed into a closed circular geometry, and then
partially opened to define the normal inner diameter of the ring. Ring 40
also may be molded or machined into a circular geometry which is then cut
and expanded to the normal inner diameter of the ring. Alternately, ring
40 may be sectioned to define a generally C-shaped configuration. The
cross-sectional profile of ring 40 is not considered critical to the
functioning of coupling 38, with representative profiles being shown in
FIG. 4 to include circular (FIG. 4A), hexagonal (FIG. 4B), elliptical or
oblique (FIG. 4C), and other polygonal (FIG. 4D) geometries.
Returning to FIG. 2, as coaxially received over the distal end 12 of tubing
14 with compression member 42, ring 40 is received within root portion 32
of tubing 14. As is shown, at least the first crest portion 34 of tubing
distal end 12 is flared or otherwise collapsed to present a
rearwardly-tapered surface, 72, which is configured for an abutting,
fluid-tight engagement with the forwardly-tapered end surface 22 of
fitting 16 (FIG. 1).
Considering next FIGS. 5-8, the assembly of coupling 38 is sequentially
described. Looking initially in this regard to FIG. 5, in accordance with
the precepts of the present invention, the coupling may be pre-assembled
for a simplified installation in the field with the mounting of ring 40
into gland 60 of compression member 42. To facilitate this mounting, a
tool, shown generally at 80, may be provided as including a cylindrical
outer guide member, 82, and a cylindrical inner plunger, 84, slidably
positioned therein. Guide member 82 is configured to receive ring 40,
shown in phantom at 40', in a partially compressed orientation, and is
insertable with ring 40 and plunger 84 into opening 46. As disposed within
opening 46, plunger 84 is slidable within guide member 82 from a rearward
first position, referenced at 86, to a forward second position, shown
superimposed in phantom at 88, to urge ring 40 out of guide member 82 and
into gland 60 of compression member 42. Ring 40 is thereby positioned
within gland 40 intermediate the rearward and forward end walls 66 and 68
thereof, and therein expands to its normal outer diameter, referenced at
d.sub.no /2, which is larger than the inner diameters of both opening 46,
referenced at d.sub.o /2, and the opening defined by shoulder portion 70.
With coupling 38 thus pre-assembly as described, ring 40 is advantageously
retained within compression member 42.
Turning next to FIGS. 6 and 7, the assembly of coupling 38 continues in
FIG. 6 with the coupling being received coaxially over the distal end 12
of tubing 14. That is, tubing distal end 12 is advanced rearwardly in the
direction of arrow 72 through opening 46 of compression member 42. As at
least the first crest portion 34 of tubing 14 is advanced through opening
46, locking ring 40 is responsive to the bearing of the crest portions
thereon in being expanded radially outwardly within gland 60. In such
orientation, ring 40 is of an expanded inner diameter, referenced at
d.sub.ei /2, which accommodates the passage of the tube outer periphery 32
therethrough. Continuing with FIG. 7, with at least the first crest
portion 34 of tubing 14 advanced to its rearward terminus, ring 40 is
thereby disposed within, for example, the first root portion 36 of the
tubing. In this orientation, ring 40 resiliently returns to its normal
inner diameter, referenced at d.sub.ni /2, which preferably is smaller
than the tubing outer periphery 32. In this way, ring 40 and compression
member 42 may be retained on the tubing 14 to facility the handling of the
assembly in the field.
Referring next to FIG. 8, the assembly of coupling 38 onto tubing 14
concludes with the flaring of the distal end 12 thereof. As was
aforementioned, the crest portion 34 of at least the first tubing
corrugation 30 may be collapsed to present rearwardly-tapered surface 72
which is shown in phantom for illustrative purposes. For effecting the
collapse of corrugation 30, a conventional flaring tool, 90, may threaded
into the rearward end portion 52 of compression member 42 and forwardly
advanced in the direction shown at 92 into a compressive engagement with
the corrugation.
Looking lastly to FIG. 9, the connection of the assembled coupling 38 and
tubing 14 to fitting 16 is illustrated. With the internally threaded end
portion 52 of compression member 42 threadably engaging the external
threads of the forward end 20 of fitting 16, the rearward surface 72 of
tubing distal end 12 is urged into a removable abutting, fluid-tight
engagement with the fitting forward end 22. Concomitantly, locking ring 40
is resiliently compressed, responsive to the bearing of camming surface 64
thereon, radially inwardly within root portion 36 of tubing 14 to a
compressed orientation having the inner and outer diameter components
referenced, respectively, at d.sub.ci /2 and d.sub.co /2. As is shown,
fitting end 22 is disposed generally parallel to or otherwise defines an
acute angle with respect to camming surface 64 to receive the ring 40 in
its radially-inwardly compressed orientation along with the flared surface
72 of tubing end 12. Particularly in such orientation, the compressed
inner diameter d.sub.ci /2 of ring 40 is provided to be smaller than the
tube outer periphery 32, and the compressed outer diameter d.sub.co /2 of
the ring is provided to be larger than the inner diametric extent,
referenced at d.sub.o /2, of compression member opening 46. With the
compression of ring 40 by camming surface 64, the forward advancement of
the tubing distal end 14 out of opening 46 is thereby delimited to effect
a robust, fluid-tight connection of the tubing to the fitting.
Thus, a unique coupling construction for corrugated tubing is described
herein which facilitates and simplifies assembly, and which may be used to
achieve a fluid-tight or other secure connection in a single operation.
Such construction additionally is adapted for use with existing fittings
as may be associated with an appliance, fuel line, or the like.
Materials of construction for coupling 38 are to be considered conventional
for the uses involved. Such materials generally will be corrosion
resistant, but particularly will depend upon the fluid or fluids being
handled. A metal material such as a mild or stainless steel or brass is
preferred for durability, although other types of materials such as
plastics may be substituted, however, again as selected for compatibility
with the fluid being transferred or for desired mechanical properties.
Preferred plastic materials include poly(ether ether ketones), polyimides,
polyetherimides, polybutylene terephthalates, nylons, fluoropolymers,
polysulfones, polyesters, and acetal homo and copolymers. Regarding
locking member 40, the selected metal or plastic material may be annealed
or otherwise heat or chemically treated to achieve the desired degree of
elasticity.
As it is anticipated that certain changes may be made in the present
invention without departing from the precepts herein involved, it is
intended that all matter contained in the foregoing description shall be
interpreted in as illustrative rather than in a limiting sense. All
references cited herein are expressly incorporated by reference.
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